Paper stock screen



June 14, 1966 a. w. SARGENT, JR 3,255,884

4 I PAPER STOCK SCREEN Filed Oct. 9, 1962 4 Sheets-Sheet l 52 INVENTOR. GEORGE W. SARGENT JR.

r 20 BY M mew ATTORNEYS June 14, 1966 w, SARGENT, JR 3,255,884

PAPER STOCK S GREEN INVENTOR GEORGE W. SARaeNr 11?.

Arron/vs vs June 14, 1966 Filed Oct. 9, 1962 G. W. SARGENT, JR

PAPER STOCK SCREEN 4 Sheets-Sheet 5 INVENTOR. GEORGE W SARGENT JR.

ATTO RNEYS J1me 1966 a. w. SARGENT, JR 3,255,884

PAPER STOCK SCREEN 4 Sheets-Sheet 4 Filed Oct. 9, 1962 INVENTOR. 650;? W. SARGE/Vr JR.

ATTORNEYS United States Patent O 3,255,884 PAPER STOCK SCREEN George W. Sargent, Jr., Beloit, Wis. (Jefferson St, Gilrnan, Vt. 05904) Filed Get. 9, 1962, Ser. No. 229,346 11 Claims. (Cl. 209-254) This invention relates generally to the paper making, water treatment, and food industries, or the like. More particularly, the invention relates to an improved separating or classifying screen for performing various functions in these industries. For example, the improved screening device finds particular though not exclusive utility in cleaning fibrous slurry prior to placing it on a paper machine for making a web; for fiber classification in refining equipment or the like; in flake and fiber classification for pulper extraction operations; and in headboxes or in a cylinder machine inlet, and the invention will be shown and described as used in paper stock sepa rating apparatus.

Generally, it is an object of the present invention to provide a compact screening apparatus which results in higher capacities with smaller orifice openings than conventional equipment.

A more specific object of the present invention is to provide an improved screening apparatus utilizing a plurality of tubular nipples or conduits which cooperate with a smooth and accurately formed surface located closely adjacent the open ends of the nipples; relative movement is provided between the nipples and the surface and the accepted stock passes between the adjustable opening be tween the nipples and the surface. In effect, a slotted type of screening action is provided and which is fully enclosed to result in a pressure tight vessel. As a result, a highly eflicient screening action provides considerably greater capacities with screening openings of smaller dimension than are possible with conventional equipment. A highly compact screening apparatus is therefore possible and one which requires considerably less power and maintenance for its operation.

Another advantage gained from the above screening device is an increased velocity of flow of the material just as it is being cleaned or classified. Consequently, flocks of material are more completely broken up and eliminated. This is particularly important, for example, at the time the stock is to be formed into paper, and the need for holy rollslor pressure distributor headers has been reduced or eliminated.

These and other objects and advantages will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings, in which: j

FIGURE 1 is a vertical sectional view through a screening apparatus made in accordance with the present invention;

FIGURE 2 is a horizontal view, in section, taken along line 22 in FIGURE 1, but on a reduced scale;

FIGURE 3 is a horizontal sectional view taken along line 3--3 in FIGURE 1, but on a reduced scale;

FIGURE 4 is a horizontal sectional view taken along line 44 in FIGURE 1, but on a reduced scale;

FIGURE 5 is a fragmentary vertical sectional view taken along line 55 in FIGURE 1, but on a reduced scale;

FIGURE 6 is an enlarged, fragmentary, vertical sectional view taken along line 66 in FIGURE 1;

FIGURE 7 is a further enlarged, fragmentary view of that encircled portion 7 as shown in FIGURE 6;

FIGURE 8 is a vertical sectional view, taken on line 8-8 in FIGURE 1, on an enlarged scale, and showing the means for adjusting the size of the screening slot;

FIGURE 9 is a horizontal, sectional view, taken along line 9-9 in FIGURE 1, but on an enlarged scale, and

3,255,884 Patented June 14, 1966 showing the drive means for reciprocating the racks of screen nozzles;

FIGURE 10 is a fragmentary view of a modified form of the invention; and

FIGURE 11 is a fragmentary view of another modified form of the invention.

The invention will be shown and described as used with a reciprocable action, but it is not intended to limit the invention to such structure. Instead, the invention may take other forms in which the cooperating surface may be either of cylindrical or flat form, and either the surface or nipples or both may be movable.

Referring in greater detail to the drawings, the screening apparatus is shown as including a generally rectangular housing H having a pair of side walls 10 and 11, a pair of end walls 12 and 13, a top 14, and a bottom 15 which form an enclosed housing.

From the top of the housing extends a floating reject discharge pipe 16 which conveys away the reject matter that floats to the top of the impure stock mixture. An air vent valve 17 is also located at the topof the housing and serves to permit entrapped air to escape from the housing and thereby permit the stock to rise to the top of the housing as indicated at the level L, so as to maintain the housing completely full during operation.

The housing H is designed so as to evenly distribute the stock into the screening apparatus and to efliciently remove the clean stock therefrom, as well as both the floating and non-floating foreign matter. The general construction of this housing is as follows.

The stock material to be cleaned is introduced into the bottom of the housing through a stock inlet pipe 20 centrally located in the bottom 15. The stock enters the central inlet chamber 21 and then flows out each end thereof and into end chambers 22 and 23 (FIGURES 1 and 2) at the ends of the housing. It will be noted that the elongated inlet chamber 21 is formed by an arched roof 24 having a peak or ridge 25 along its top side. From the end chambers 22 and 23 the stock then enters the four vertical risers 26, 27, 28, and 29, respectively, which are located at the four corners of the housing, and are indicated by the phantom lines in FIGURE 2. Thus, the risers conduct the supply of stock upwardly at the four corners of the housing.

As shown clearly by FIGURE 4, the stock leaves the four risers and enters the main chamber 30 of the housing via the horizontal and similar passages 31, 32, 33 and 34. Passages 31 and 33 are located, respectively, above passages 32 and 34, and passages 31 and 32 are connected at different heights to risers 26 and. 27, while passages 33 and 34 are connected at different heights to risers 28 and 29.

The horizontal passages 31 to 34 communicate with the main chamber 30 through a series of various size openings 35, 36, 37, 38, and 39. The central opening 35 is the largest, and then these openings get progressively smaller from each side of the center opening.

By providing openings of gradually decreasing size as they are located from the center of the housing, more stock is introduced in the central portion which results in a sweeping flow action of the stock from the center of the housing and toward each side thereof. This has the effect of producing good distribution and circulation of the entire contents of the housing, particularly since the stock is introduced along both sides of the housing and at different elevations.

Located within the main chamber 30 of the housing are three sets of screens S, S1, and S2, although other numbers of sets could be used.

As these screen sets are similar to one another, only one will be described in detail. Each set includes a series of parallel, stationary bars 40 which are fixed together at their ends by cross braces a in the housing at each end. The bars each have an accurately finished, lower flat surface 41 which cooperates with its respective set of nipples 42 to define a slot or opening 43 therebetween. It is through the screen provided by these slots 43 that the accepted stock passes through the nipples 42 and into the transverse conduits 45.

The accepted stock passes from each end of the conduits and into and downwardly in the vertical plenums 47 and 48 located at each side of the housing. The accepted stock is then withdrawn from the housing via the discharge openings 49 and 50 in the lower side 15 of the housing.

The rejected stock, such as foreign material that fails to'pass through the slotted screen openings 43, eventually falls downwardly and is withdrawn through the reject pipes 52 and 52 in the bottom of the housing.

The arched roof 24, curved side arches 51 and 51a, and the downwardly converging pairs of inclined floors 54 and 54a prevent an accumulation of the rejected matter in the bottom of the housing.

The previously mentioned nipples 42 are formed as a series of tubular conduits which have an open end 42a that is flat and lies closely adjacent the respective flat surfaces 41 of the bars 40. The nipples are shown (FIGURE 6) as being arranged in two rows along the length of their conduits 45. The ends of the conduits 45 are rigidly secured in the slides 55, 56 which have apertures 57 (FIGURE 5) therein which are in alignment and communication with the interior of the conduits 45, as previously mentioned.

The conduits 45 of any one set of screens, together with their slides and 56, are reciprocated as a unit. For this purpose, opposed ways 60 and 61 are provided for each slide 55 and 56 and are rigidly fixed in the housing. Pressure lubricating passages 63 and the ports 64 leading from a pressure manifold passage 66 may be formed in the ways to provide a hydrostatic bearing between the slides and their ways. Guide blocks 66 are secured to the slides and insure alignment of the reciprocable unit with the ways.

From FIGURE 7 it will be noted that the ends of the nipples are provided with an annular flange 70 which has a sharp edge 71 therearound. The entire end of the nipple, however, is flat and finely finished. Thus, a fillet is provided between the flat end 42a and the main body of the nipple which causes an orderly circulation or flow of material, as indicated by the arrows, in this area as the nipples are reciprocated. This action, together with the sharp edge 71 that lies closely adjacent surface 41, i

has a tendency to assist in the rejection of foreign material M from the opening 43, and prevents jamming of foreign material in this opening as relative movement takes place being the nipples and their cooperating surface.

It Will be appreciated that the bars 40 need not be continuous, but only the sufficient flat surface area is provided to cover the ends of the nipples regardless of their position.

The means for reciprocating the racks of nipples is shown clearly in FIGURE 9, and one of these drive units would be provided for each set of screens and all units connected by a common, vertical drive shaft 80.

The shaft 81 of the rack of nipples is rigidly secured thereto by the bracket 82 (FIGURE 1) and this shaft terminates in a pad 83 at the end wall 13 of the housing. A flexible seal 84 seals the opening 85 in the wall and pad 83 abuts against this seal.

Flexible seal 84 eliminates the need for a sliding shaft seal in the wall 13, and permits ready assembly or disassembly of the drive.

Another shaft 86 is arranged coaxially with shaft 81 and is rotatably mounted in the drive housing 87 secured to wall 13. The common drive shaft 80 rotates shaft 86 through the constant mesh gears 88 and 89. A wobble plate 90 is mounted by its sleeve 91 for rotation with shaft 86 and rotates between the fixed stops 92 and 93 secured to housing 87. Sleeve 91 is splined to shaft 86 and thereby reciprocates on the shaft as the latter rotates. The pad 94 on the end of sleeve 91 also abuts against seal 84 in alignment with shaft 81 and imparts reciprocatory movement thereto. A spring 95 urges shaft 81 to the left as viewed in FIGURE 9.

A counterbalance mass 97 may be similarly mounted on the other end of shaft 86 for transmitting an opposing thrust through the housings to counterbalance the inertia forces developed by the reciprocating nipple racks.

FIGURE 8 shows the means for adjusting the size of the screening slot 43, in other words, the distance between the surface 41 of bars 48 and the open end of the nipples 42. This is accomplished by vertically moving or adjust ing the rack of bars 40, but of course other forms of adjustment may be provided, or the nozzle racks may be adjusted, thus providing relative adjustment between the nozzles and bars.

This adjusting means includes four vertical shafts, only three of which 96a, 96b, and 960 are shown, but which are secured to the corners of the racks of bars, as by extending through the cross braces 48a fixed to each end of the bars. These vertical shafts extend through flexible seals 98 in the top 14 of the housing and are vertically adjustable by the wedges 97a slidably mounted in complementary blocks 99 on the top 14. An adjusting rod 98a threadably engages the wedges to shift the latter as the rod 98a is rotated by hand wheel 99a.

The modifications shown in FIGURES 10 and 11 show the invention as applied to a rotary type of screening apparatus in which a rotor 180, such as a cylinder, rotates about a vertical axis 101 and within a cylinder 102.

Any number of nipples 103 may be secured to the rotor and each has an open end 103a and an annular flange 104 with a sharp edge 105. The nipples are hollow and communicates with the interior of the stator for passing acceptable stock thereto.

The raw stock is deposited in any known manner into the annular path 107 formed between and by the stator and rotor, and the accepted stock is passed through the nipples while the rejected stock is collected at the bottom of the path 107, in a conventional manner and withdrawn therefrom.

In the FIGURE 10 device, the nipple extends radially from the rotor and its end lies closely adjacent the cylindrical surface 110 past which it rotates. Due to the curvature of the surface 110, the end of the nipple should be of complementary shape so as to provide a uniform screening slot 111.

The FIGURE 11 device has the nipples 103b arranged longitudinally with respect to the axis of the rotor, and fixed thereto by the hollow bracket 103a. The cooperative screening surface 112 is flat and formed as a ring like fiat plate that is supported from the stator by brackets 113 in any suitable manner. Thus the nipples sweep in one direction past. the continuous surface 112 and form a screening slot 114 therewith.

The size of the screening slot 114 is readily adjustable by axially shifting the rotor relative to the stator by any suitable adjusting means.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention:

1. Paper stock screening apparatus comprising, a housing for containing paper pulp stock, a plurality of tubular nipples mounted in a chamber in said housing and each having an open free end, a cooperating surface located .closely adjacent said free ends and thereby defining a screening space therebetween, said surface being smooth and continuous and having means for maintaining said surface at a constant distance from said free ends, and means for providing relative movement between said nipples and said surface whereby said free ends move past said continuous surface at a constant distance therefrom and acceptable stock passes through said screening space and through said open ends and into said nipples, said housing having an outlet for accepted stock, and conduit means placing said nipples in communication with said outlet.

2. Paper stock screening apparatus comprising, an enclosed housing for containing paper pulp stock, a plurality of rows of tubular nipples mounted in a chamber in said housing and each nipple having an open free end, a smooth and rigid surface located closely adjacent said free ends to define a screening space therebetween, said surface being continuous and uninterrupted, and means for providing relative movement between said nipples and said surface, and means for maintaining said open ends at a constant distance from said surface, thereby causing acceptable stock to pass through said screening space and through said open ends and into said nipple, said housing having an outlet for accepted stock, and conduit means placing said nipples in communication with said outlet.

3. Paper stock screening apparatus comprising, an enclosed housing for containing paper pulp stock, said housing having a stock inlet and also having internal passages at spaced locations around said housing for distributing said stock uniformly in said housing, said housing also having an outlet for accepted stock and a reject opening for rejected stock, a plurality of tubular nipples mounted in a chamber in said housing and each having an open free end, a cooperating surface located closely adjacent said free ends and thereby defining a screening space therebetween, said surface being smooth and continuous and having means for maintaining said surface at a constant distance from said free ends, and means for providing relative movement between said nipples and said surface whereby acceptable stock passes through said screening space and through said open ends and into said nipples, and conduit means for placing said nipples in communication with said outlet.

4. Paper stock screening apparatus comprising, a housing for containing paper pulp stock, a reciprocable rack in said housing, a plurality of tubular nipples on said rack and each having an open free end, a, stationary cooperating surface in said housing and located closely adjacent said free ends and thereby defining a screening space therebetween, said surface being smooth and continuous and having means for maintaining said surface at a constant distance from said free ends, and means for reciprocating said rack whereby said nipple free ends move past said continuous surface at a constant distance therefrom and acceptable stock passes through said screening space and through said open ends of said nipples, said housing having an outlet for accepted stock, and conduit means placing said nipples in communication with said outlet.

5. Paper stock screening apparatus comprising, a housing for containing paper pulp stock, a plurality of rows of tubular nipples mounted in a chamber in said housing and each nipple having an open free end, rigid bars mounted in said housing and having cooperating surfaces located closely adjacent said free ends and thereby defining a screening space therebetween, said surface being smooth and continuous and having means for. maintaining said surface at a constant distance from said free ends, and means for providing relative movement between said nipples and said surfaces whereby said nipple free ends move past said continuous surface at a constant distance therefrom and acceptable stock passes through said screening space and through said open ends and into said nipples, said housing having an outlet for accepted stock, and conduit means placing said nipples in communication with said outlet.

6. Paper stock screening apparatus comprising, an enclosed housing for containing paper pulp stock, a rack reciprocally mounted in said housing, a plurality of rows of tubular nipples on said rack and each nipple having an open free end, rigid bars stationarily mounted in said housing in parallelism with said rows of nipples, said bars each having a cooperating surface located closely adjacent said free ends and thereby defininga screening space between said nipples and bars, said surface being smooth and continuous and having means for maintaining said surface at a constant distance from said free ends, and means for reciprocating'said racks of nipples whereby said nipple free ends move past said continuous surface at a constant distance therefrom and acceptable stock passes through said screening space and through said open'ends and into said nipples, said housing having an outlet for accepted stock, and conduit means placing said nipples in communication with said outlet.

7. Paper stock screening apparatus comprising, a housing for containing paper pulp stock, a plurality of tubular nipples in said housing and each having an open free end, each nipple having a radially extending annular flange around said open end, said flange terminating in a sharp edge, a cooperating surface located closely adjacent said free ends to define a screening space therewith, said surface being smooth and continuous and having means for maintaining said surface at a constant distance from said free ends, and means for providing relative movement between said nipples and said surface whereby said nipple free ends move past said continuous surface at a constant distance therefrom and acceptable stock passes through said screening space and through said open ends and into said nipples, said housing having an outlet for accepted stock, and conduit means placing said nipples in communication with said outlet.

8. Paper stock screening apparatus comprising; an enclosed housing for containing paper stock, said housing having a stock inlet, internal passages at spaced locations around the housing for distributing stock uniformly into the housing at various locations in said housing, an outlet for accepted stock, and a reject opening for rejected stock, a rack reciprocally mounted in said housing, a plurality of rows of tubular nipples on said rack and each nipple having an open free end, rigid bars stationarily mounted in said housing in parallelism with said rows of nipples, said bars each having a cooperating opposing surface located closely adjacent said free ends and thereby defining a screening space between said nippies and surfaces, said surface being smooth and continuous and having means for maintaining said surface at a constant distance from said free ends, means for reciprocating said racks of nipples whereby said open ends move along their respective opposing surfaces at a constant distance therefrom, thereby causing acceptable stock to pass through said screening space and through said open ends and into said nipples, and conduit means in said housing for placing the interior of said nipples in communication with said outlet.

9. Rotary screening apparatus for paper stock comprising, an enclosed outer cylinder having a smooth continuous and circular screen-defining surface therein, a rotor rotatably mounted in said cylinder and forming an annular chamber therewith for containing paper pulp stock, means for introducing stock into said annular chamber, a plurality of tubular nozzles secured to and extending from said rotor and into said chamber, said nozzles each having an open free end and being in communication with the interior of said rotor, said surface extending over the periphery of said nozzles, said nozzle free ends located closely adjacent said circular surface to define a screening slot therewith and for movement at a constant distance in respect thereto, whereby accepted stock passes through said slot and nozzles and into said rotor.

10. Rotary screening apparatus for paper stock comprising, an enclosed outer cylinder having a smooth continuous and cylindrical internal surface, a rotor rotatably mounted in said cylinder and forming an annular chamber therewith for containing paper pulp stock, means for introducing stock into said annular chamber, a plurality of tubular nozzles secured to and having their longitudinal axes extending radially outwardly from said rotor and into said chamber, said nozzles each having an open free end located closely adjacent said cylindrical surface to define a screening slot therewith, said surface extending over the periphery of said nozzles and for movement at a constant distance in respect thereto, and through which slot accepted stock passes into said nozzle and rotor.

11. Rotary screening apparatus for paper stock comprising an enclosed outer cylinder having a fiat, continuous and circular surface therein and arranged transversely to the axis of said cylinder, said surface being continuous, a rotor rotatably mounted in said cylinder and forming an annular chamber therewith for containing paper pulp stock, means for introducing stock into said annular chamber, a plurality of tubular nozzles secured to and extending from said rotor and into said chamber, the longitudinal axes of said nozzles being arranged in general parallelism with the axis of said rotor, said nozzles each having an open free end located closely adjacent said fiat surface to define a screening slot therewith and for movement at a constant distance in respect thereto, said surface extending over the periphery of said 5 nozzles, whereby accepted stock passes through said slot and into said rotor.

References Cited by the Examiner UNITED STATES PATENTS 289,1;87 11/1883 Voith 209-269 824,720 7/ 1906 Hunnicutt 209-397 1,098,927 6/1914 Ward 210-360 X 1,187,731 6/1916 Hang 209-270 1,794,916 3/1931 Naugle 210-416X 1,948,947 2/1934 OKeefe 210-402 2,002,404 5/ 1935 Lamort 209-270 2,707,905 5/1955 Mathewson 209-270 2,809,591 10/1957 Imset 210-416 X 3,064,812 11/1962 Wehner 209-396 FOREIGN PATENTS 965,481 6/1957 Germany. 710,540 6/ 1954 Great Britain,

HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner. 

1. PAPER STOCK SCREENING APPARATUS COMPRISING, A HOUSING FOR CONTAINING PAPER PULP STOCK, A PLURALITY OF TUBULAR NIPPLES MOUNTED IN A CHAMBER IN SAID HOUSING AND EACH HAVING AN OPEN FREE END, A COOPERATING SURFACE LOCATED CLOSELY ADJACENT SAID FREE ENDS AND THEREBY DEFINING A SCREENING SPACE THEREBETWEEN, SAID SURFACE BEING SMOOTH AND CONTINUOUS AND HAVING MEANS FOR MAINTAINING SAID SURFACE AT A CONSTANT DISTANCE FROM SAID FREE ENDS, AND MEANS FOR PROVIDING RELATIVE MOVEMENT BETWEEN SAID NIPPLES AND SAID SURFACE WHEREBY SAID FREE ENDS MOVE PAST SAID CONTINUOUS SURFACE AT A CONSTANT DISTANCE THEREFROM AND ACCEPTABLE STOCK PASSES THROUGH SAID SCREENING SPACE AND THROUGH SAID OPEN ENDS AND INTO SAID NIPPLES, SAID HOUSING HAVING AN OUTLET FOR ACCEPTED STOCK, AND CONDUIT 